ARCHIVED REPORTS XR0012596 - Laserfiche WebLink

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l 5,6 Y Tracer Research Corporation i I injections)in volumes ranging from 1 uL to 2 mL,depending on the VOC concentration at any particular location. anted from 2-22 inches Hg. The maximum pump vacuum Sample probe vacuums r was Maasnred at 240 inches Hg- pNpI,Y'I'ICAL PROCEDURES matograph was used for the soil gas analyses. It was A Varian 3300 gas chro equipped with a flame ionization detector (FIB). Camp�a�in a temperature controlled �were separated on a 6' by 1/8" OD packed column with OV-101 as the stationary p overt. Nitrogen was used as the carrier gas. Hydrocarbon compounds detected in the samples were ie2ntified by chromat retention time. Quantification of compounds was achieved by contparisa. of the detector response of the sample with the response measured for calibration standards (external standardization). Instrument calibration checks were run periodically throughout fire day r and system blanks were run at the begianing of the day to check for contamination in the soil gas sampling equipment. Air samples were also routinely analyzed to check for background levels in the atmosphere. Detection limits for the compoueds of interest were a function of the injection volume as well as the detector sensitivity for individual compounds. Thus the detection limit varied with the sample size. Generally, the larger the injection size the greater the sensitivity. However, peaks for compounds of Interest were kept within the linear range of the analytical equipment. If any compound had a high concentration, it was necessary to use small injections, and in some cases to dilute the sample to keep it within linear range' This may have caused decreased .detection limits for other compounds in the analyses. The detection limits for the hydrocarbon compounds were approximately 0.03 ug/L. Detection limits were dependant upon the conditions_of the measurement, ill 4